This paper studies the NC grinding process for Isometric Polygonal Profiles (IPP) with self-made machine tools accessories, and establishes the time series model of the grinding process by means of measuring and analyzing the vibratory signal in the grinding process. The grinding experiment indicates that the Surface formative motions of IPP can be achieved with the step-motor-driven accessories and it is reasonable to design the grinding machine for IPP according to the principle. This method solves the technical problems in IPP NC processing and can act as an important elicitation and illustration for NC processing other polygonal profiles.